1. Field of the Invention
The present invention relates generally to the field of skateboarding and, more particularly, to truck assemblies for use when skateboarding at high rates of speed.
2. Background
Skateboarding has become one of the more popular activities requiring a recreational device used by a rider to move across a solid support surface. A conventional skateboard typically includes a narrow, elongated platform or deck with an uppermost riding surface and a bottom surface to which a pair of wheel assemblies may be attached. The deck is sufficiently sized to allow the rider to be able to place at least a portion of both feet on the uppermost surface when riding the skateboard.
While initial skateboard decks were generally planar and made primarily out of wood of a single layer, more modern skateboard decks are known to incorporate laminated forms of two or more layers in a variety of non-planar shapes, including having a generally upwardly bent nose and/or tail end, and may be made out of a variety of different types of materials, including various metal, thermoplastic and composite materials.
The incorporation of wheels allows the skateboard to roll across a support surface due to gravity and/or a propelling action by the rider. As well known by persons familiar with skateboards, the rider also typically uses one foot to push against the ground in order to propel the skateboard and uses his or her body to tilt the deck to change the skateboard's direction of travel.
The typical wheel assembly used on most conventional skateboards includes a truck assembly with a baseplate secured to the bottom surface of the deck and a pair of wheels rotatably supported by the truck assembly. The typical skateboard truck assembly (the “truck”) includes a hanger that may be secured to the baseplate by a kingpin, one or more compressible bushings which permit the hanger to pivot relative to the baseplate and the deck, and an axle which is supported by the hanger. One wheel is rotatably connected to each of the distal ends of the axle with each wheel being free to spin independently.
For the conventional skateboard, there is typically a wheel and truck assembly located toward the front and back ends of the deck and the truck assemblies are fixedly attached to their respective baseplates with mechanical connectors, such as rivets, screws, bolts and/or specially configured adhesives. The pivoting motion allows the rider to tilt the deck and gain more control of the skateboard's movement. Often, the wheels of a conventional skateboard are made out of polyurethane or like materials and the various structural components of the truck assembly are made out of metal, such as aluminum or steel, or various composites.
Each pair of wheels is typically mounted on a single axle per truck that is substantially parallel to the riding surface. While the typical direction of travel for a skateboard is along the longitudinal axis of the deck, the axles may be displaced by tilting the board as the rider leans thereby causing the hangers to pivot relative to the deck and orienting the wheels so that they steer the skateboard generally along the circumference of a circle in the direction of the lean or tilt.
While the foregoing generally describes a conventional skateboard, skateboards have continued to evolve as companies try to make them lighter and stronger, and continue to try to improve on their performance. As skateboards developed and improved in performance, riders continue to push the limits. One place to push the limit is on a slope or hill and many seek such locations out specifically to ride fast. When the rider rolls down the slope, he or she typically controls the speed of the skateboard by performing a generally zigzag or carving movement that slows the speed of the skateboard, thereby allowing the rider to safely control the skateboard. Alternatively, dragging one foot may be useful in controlling speed. Often, riders uncomfortable with higher speeds will simply walk down the hill or start a lower section of the hill until a certain level of confidence and skill is attained.
Besides maintaining control at higher speeds under normal conditions, when riding straight downhill or being pulled at high speeds, riders often encounter an undesirable condition known as “speed wobble” (also known as shimmy, wheel wobble, or death wobble) wherein the wheels and hanger begins to rock, tilt, and twist relative to the deck. In general, speed wobble describes the undesirable back and forth oscillation of the hanger and attached wheels of the skateboard creating a growing instability. This further leads to a rocking deck as each time the hanger tilts or pivots from a straight ahead (normal) alignment, the deck rocks to one side and then the other due to the oscillation which then typically increases in amplitude. The feedback from the wheels as they roll across the support surface exacerbates the problem. As the deck begins to tilt up and down an undesirable turning motion (both roll and yaw may be impacted) may be introduced and must be corrected to maintain control. Instead, typically, the rider over-corrects or cannot correct fast enough. Moreover, once a critical speed is reached, the oscillations may be too great to correct. This can occur both on long boards and regular sized skateboards.
To deal with speed wobble, riders are often advised to tighten the trucks. However, this only helps to a certain extent and reduces the ability to steer and maneuver and successfully make turns. Maintaining loose trucks may allow for greater maneuverability but facilitates wobble. In other words, stability may be traded for maneuverability, which is not desirable in most skateboarding scenarios. However, speed wobble is particularly dangerous when riding downhill and most riders may be ejected off a skateboard due to speed wobble, sometimes with serious results.
Speed wobble may also occur when the rider is not comfortable thus tensing the muscles in his or her ankles which causes the rider to over-correct his or her movements. This in turn may cause the rider's body and board to turn from side to side uncontrollably eventually resulting in the rider getting trampolined off forwards and sideways unless the rider can recover from the wobbles. Thus, another advised approach is to merely relax and ride with less tension to avoid tensing up due to panic and taking a mental approach. Once the rider commits to the speed and lack of control this may allow for both carving for control purposes but also tucking which provides tremendous speed. However, this approach takes a lot courage and experience before mastering and the speed wobble is a likely inevitable in any event.
Other solutions offered to improve stability besides tightening the trucks include using wider tricks and wheels, lowering the trucks, using harder bushings, and/or keeping most of the rider's weight over the front truck. Lower trucks and harder bushings may also provide more stability as well. However, too tight or too loose of trucks may pose problems as well when descending a steep hill, and it is difficult to test out different combinations to find a suitable solution. Moreover, changing out these parts for different conditions takes time away from riding and adds expense and inconvenience due to keeping various parts on hand.
While certain other proposed solutions attempt to cushion the ride by employing a pneumatic (gas) compression strut skateboard truck assembly (U.S. Pat. No. 6,224,076 to Kent) or a dual elastomeric suspension system (U.S. Pat. No. 7,044,485, to Kent at el.), the focus of the truck assemblies in these patents is on reducing single direction compressive shock forces generated by rolling over uneven ground surfaces. However, speed wobble is an undesirable oscillation between the hanger and wheels and the deck that requires an entirely different set of principles than that of reduction of single direction linear shock forces.
Thus, while the foregoing general advice solutions are at least intended to provide better stability by changing out parts or tightening components, this comes at the sacrifice of maneuverability, time, and expense and still does not adequately address speed wobble. In addition, while the patented solutions may provide some degree of shock absorption by introducing a cushioning element to oppose compressive forces so as to purportedly improve ride quality, they are not designed to address the speed wobble issue. What is needed, therefore, is an improved skateboard truck assembly for use with skateboards that allows the rider to reduce or prevent speed wobble encountered at higher speeds such as when riding downhill allowing for increased control of the skateboard without sacrificing maneuverability while being compatible with a wide variety of different types of skateboards.